Puberty is a physiological process, when the child’s body matures into an adult at a physical and functional level. The word puberty is derived from the Latin word Puberatum, which means age to maturity. It is a process through which the young adult develops the capability for sexual reproduction. Puberty is initiated by hormonal changes induced by the brains to gonads (i.e. the ovaries in girls and the testes in boys). The gonads produce hormones which introduces libido and brings about physical changes such as height and weight changes; development of sex organs; breast development; bone, blood, skin, muscle changes etc. Puberty marks the onset of transformation from a child to an adult.
Puberty refers to only the physiological changes associated with entering adulthood. It should not be confused with adolescence which refers to the psychological and emotional changes associated with entering adulthood.
How Long does Puberty Lasts on Average?
The duration of puberty is different among girls and boys. It also depends on each individual’s physiology and genetic make-up. On an average, puberty lasts for about 2 to 5 years. Among the girls, puberty starts between the age of 9 to 14 years and ends between 15 to 17 years. For boys, the puberty starts a little later. It begins usually between the age of 11 to 13 years and ends around the age of 16 to 17 years. However, it is important to understand that every child is different, and there are no set rules for when the puberty should start or end, or for how long it should last. Studies have shown that, the average age for onset of puberty has lowered in the 21st century as compared to that in the 19th century. This is more evident among girls than boys. This could be due to several factors such as changes in lifestyle, improved nutrition leading to rapid growth and development, external environmental factors, availability of processed food etc. Exposure to endocrine disruptor such as xenoestrogens (from food or environmental issues) can also affect the onset of puberty.
In girls, the major landmark that marks the onset of puberty is menarche (or the first menstruation or periods). Among the boys, onset of puberty is marked by the first ejaculation. If puberty commences before the expected time it is called as precocious puberty, and if the puberty commences after the expected time it is called as delayed puberty.
Physical Changes Associated with Puberty
Physical Changes during Puberty in Girls:
- Height and Weight: Among girls, 20% of the adult height is attained during puberty. Girls usually grow taller during the first few years of puberty. 50% of adult weight is gained during puberty. There is more weight gain in the hips, thighs, breasts and stomach area as compared to other body parts. The body fat percentage usually doubles during puberty.
- Sexual Development: Breast starts to develop around the age of 9 to 11 years. It starts as a small lump under the nipples and it is often accompanied by tenderness in the area. This is called as breast budding. Around the same phase, pubic hair begins to grow followed by hair growth in the underarm areas and also over the legs. As mentioned earlier, menstruation begins around the same time and for the first couple of years it is often irregular.
- Acne and Body Odour: Hormonal changes in the body often cause skin breakouts over the face, back and upper arms. Hormonal changes also cause increased sweating.
Physical Changes during Puberty in Boys:
- Height and Weight: About 20% of adult height is gained during puberty. However, unlike girls, they gain their height usually towards the end of puberty. 50% of adult weight is gained during puberty. They have lower body fat percentage and increased muscle towards the end of puberty.
- Voice Changes: Boys generally develop a deeper and manly voice during puberty.
- Sexual Changes during Puberty: Puberty is accompanied by increase in the size of the testicles while they drop lower in position. The scrotum usually becomes darker, looser and there may be appearance of dots and small bumps over the scrotum. The penis grows bigger in size and matures during puberty. Soon after this, there is hair growth in the pubic area. This is accompanied by hair growth in other areas such as chest, face, legs and underarms. There are episodes of erection (i.e. stiffness of the penis due to increased blood supply) and nocturnal emissions (i.e. wet dreams) during puberty. This is the natural body reaction to production of sperm.
- Acne and Body Odour: As seen in girls, puberty is accompanied by hormonal changes even among boys. This causes appearance of acne over face, neck back or upper arms. There is also increase in body odour due to profuse sweating.
Puberty is a natural process of growth. However, the exact time of onset and ending cannot be predicted accurately. The total duration of puberty also varies from one person to another and also between genders. In general, on an average, puberty lasts for 2 to 5 years and it accompanied by many changes, both externally as well as internally.